The invention relates generally to processing of semiconductors.
In recent years, transparent conductive oxides (TCOs) have attracted attention due to the high demand for optoelectronic devices such as solar cells, light emitting diodes (LEDs), and organic light-emitting diodes (OLEDs). Currently, indium tin oxide (ITO) is the most commonly used TCO material due to high electrical conductivity and high optical transparency in the visible region (˜80%). However, ITO has several limitations. Notably, its transparency in the near-UV region decreases rapidly and there exists a low supply of indium. Hence, it makes the cost of ITO fabrication very high.
In contrast to the disadvantages of ITO, several investigations had been done one the zinc-oxide (ZnO)-based materials such as gallium zinc oxide (GZO), indium zinc oxide (IZO), aluminum zinc oxide (AZO), and indium gallium zinc oxide (IGZO). These compounds are better alternatives due to their low toxicity, high carrier mobility, excellent environmental stability and superior chemical selectivity. Among them, IGZO is a new prospective material used as TCO on optoelectronic devices due to its high transmittance, low processing temperature and excellent surface smoothness. However, the electrical resistivity of IGZO is still high for its application as transparent electrode. To decrease the electrical resistivity of IGZO, several studies have been conducted to investigate the relationship between stoichiometry and electrical properties or controlling deposition parameters. However, little attention has been paid to the influence of post-deposition processing parameters on optical and electrical properties of IGZO.
Consequently, considering such limitations of previous technological approaches, it would be desirable to have a system and method for making an IGZO thin film with improved optical and electrical properties with a reduced annealing time.